Cam and slide motion converting means for converting rotary motion to reciprocating motion



Oct. 23, 1956 c. B. REDRUP ET-AL 2,

CAM AND SLIDE MOTION CONVERTING MEANS FOR CONVERTING ROTARY MOTION TO RECIPROCATING MOTION Filed Jan. 6, 1954 I 2 Sheets-Sheet 1 $4 jzzve zivzes C 3.36 drab 0 C. MOTI MOTION Oct. 23, 1956 CAM ANDRgL 2 Sheets-Sheet 2 Filed Jan. 6, 1954 Charles Benjamin Redrup and John Arnold Redrup, Heaton Moor, Stockport, England Application January 6, 1954, Serial No. 402,438

Claims priority, application Great Britain November 12, 1951 Thus invention relates to the construction of engines,

pumps, compressors, motors and the like and has for its object to provide an improved compact construction in which the reciprocatory motion of the engine or motor pistons is directly converted into rotary motion at the 0 output shaft or the rotary motion of the input shaft is directly converted into reciprocatory motion of the pump or compressor pistons without the use of cranks, connecting rods and the like.

The invention consists in a construction of engine, 5 pump, compressor or motor comprising a series of piston type units disposed around a rotor having peripheral cam grooves therein which are engaged by raised peripheral collars on the pistons, the latter being free to revolve sothat the reciprocatory movements of the 0 pistons and the rotary movements of the rotor are co-related, there being a ring or liner co-axial with the rotor to receive the lateral thrust of the collars.

The invention further consists in a construction as aforesaid in which an engine, pump, compressor, motor or the like comprises a series of opposed-piston type units disposed around an input or output rotor or coupled rotors, each rotor comprising at least one drum or cylinder with peripheral cam grooves therein which are engaged by raised peripheral collars on the pistons, so that reciprocation of the pistons causes rotary movement of the rotor or rotors, or rotary movement of the rotor or rotors causes reciprocatory movement of the opposed pistons.

The important advantage of the said constructions is that the pistons are symmetrical and light and can turn freely about their axes so that wear of the pistons with their collars is evenly distributed due to the turning of the pistons consequent upon the inter-engagement of the collars and the cam grooves in the rotor. Further all lateral thrusts on the pistons caused by the inter-engagement of the collars and cam grooves are effectively absorbed. The symmetrical piston'design also ensures fairly uniform expansion and contraction of the pistons due to heat changes.

Referring to the accompanying explanatory drawings:

Figure l is a diagrammatic sectional view of an engine with horizontally opposed pistons constructed in one convenient form in accordance with this invention.

Figure 2 is an end View of the engine.

Figure 3 is a detail sectional view showing a cylinder in which the opposed pistons work, with the transfer, inlet and exhaust ports.

The engine illustrated in Figures 1-3 comprises four pairs of opposed pistons a, b which reciprocate in cylinders c in which are transfer ports d, inlet ports e and exhaust ports 1. Each cylinder also has therein a spark ing plug at g.

The combustible fuel passes through a fixed pipe or tube h (which has a spring loaded non-return valve i nited States Patent 0 thereon) into the end ofeach piston adjacent the piston head, and thence through ports j in the piston skirt to the transfer port-s d, when each pair of pistons is at about the end of its outward stroke as shown in'- Figure 1. Only one non-return valve i is shown but similar valves are on all the pipes h. From the ports j and d, the fuel mixture passes into the transfer duct k and so to the inlet ports e whence it is delivered into the cylinder c between the pair of opposed pistons therein. At the end of the compression strokes of each pair of pistons, the charge is fired by the sparking plug at g and at the end of the power stroke of each pair of pistons, exhaust takes place via the exhaust ports 1" and pipe m, Figure 3.

Each piston has upon its skirt three raised collars 11, two of which engage in peripheral cam grooves o in drums or cylinders p on the power shaft q whilst the third collar engages a peripheral cam track r on the drum or cylinder. Reciprocation of the pistons a, b results in rotary movement of the drums p and of the power shaft q to which the drums are secured.

The collars it ride upon the internal surface of a ring t of hardened steel which is adapted to receive any lateral thrust on the collars due to the inter-engagement of the collars and the cam grooves.

The engines shown are of the two-stroke type with their cylinders carried in the engine frame around the rotor drums p and power shaft q.

There may be any desired number of opposed-piston type units, e. g. twelve around a rotor, and each rotor drum p may have two or more cam grooves therein shaped to give one turn of each rotor for two or more complete reciprocations or back and forth movements of the pistons which engage the rotor. There are any suitable number of raised collars n on each piston to engage the like number of cam grooves on the rotor drums with which such pistons co-operate. A series of sets of opposed-piston type units may engage rotor drums on a common shaft or axially aligned and coupled shafts.

The cylinders c may be formed in segments which are bolted together in a ring around the rotor.

The cam grooves in the two rotors p engaged by the opposed pistons of the several units disposed around the rotor, may provide for a lead of one set of pistons of the opposed-pairs with relation to the other set to facilitate eflicient port functioning and operating conditions.

With our improvement as applied to an engine, we obtain a very compact construction giving a very high power output from a relatively small diameter power unit.

It will be appreciated that our improved arrangement of opposed-pistons around rotors can be utilised for pumping or compressing purposes, the exhaust ports being substituted by delivery ports disposed between the pairs of pistons when they are adjacent to one another at the ends of the compression strokes. The rotors p then drive the pistons.

We claim:

1. A motion converting means comprising in combination, a drive shaft, a rotor concentrically mounted on the drive shaft, means defining a series of spaced apart cam grooves in the periphery of the rotor, a plurality of reciprocable and freely rotatable pistons mounted coaxially about the rotor, a series of spaced apart collars 'on the periphery of each piston, each collar being maintained in constant contact with one of the cam grooves of the rotor and each of the pistons having a plurality of reciprocatory movements for each complete revolution of the drive shaft, and a ring co-axial with the rotor surrounding said pistons with the spaced collars riding on the ring and the ring serving to receive the lateral thrust of the collars.

References Cited in the file of this patent UNITED STATES PATENTS 1,374,315 Murphy Apr. 12, 1921 4, Dudley Aug 14, 1923 Heideman Sept. 24, 1940 Myard Dec. 23, 1952 FOREIGN PATENTS France Dec. 28, 1912 France May 2, 1927 France Feb. 5, 1932 

